Who are these people who will not accept a receipt but need a certificate?And what sort of security measures must these certificates have that people, who apparently think a receipt is not proof enough, will be satisfied that the certificate is genuine?Do these people want certificates for other maintenance tasks too, or is this the only thing they care about enough to warrant needing a certificate?People are strange.

Michael

Valid point… a receipt is fine enough. Have that and no need for certificate

The certificate sou ds like as big red says a way to justify the cost , it’s not hard to clean and acf 50 your bike yourself,it’s not a magic potion that only authorised and trained people are allowed to apply.